US4342076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Transistor turn off current sensing circuit
Assignee: Sundstrand Corp
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Filing: 1981-02-12
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Granted: 1982-07-27
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Expires: 2001-02-12
Abstract
Abstract A transistor current sensing circuit is provided for a power output transistor whose drive circuit includes a current controlled feedback transformer that has a current limited direct current source connected to the secondary winding of the transformer wherein the change in voltage level of the secondary winding upon the completion of turn-off of the output transistor is used as a signal to initiate turn-on of another associated transistor.
Inventors
- 👤 Mark A. Rosswurm
- 👤 Joseph M. Urish
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:28
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/538; H02M7/53803
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
136 words
Power transistor circuitry with current sensing comprising: a first output transistor connected to control conduction between an input terminal and an output terminal; means for selective application and removal of base drive current to said output transistor, said means comprising a current controlled feedback transformer, said current controlled feedback transformer having a secondary winding with a tap connected to a current source; means for monitoring the voltage of said secondary winding as an indication of the current conducted by said output transistor, said voltage exhibiting a change from a first low level to a second higher level upon the completion of the turn-off period of said output transistor; and means for initiating a turn-on base signal for a second output transistor in response to said change in voltage of said output voltage of said current source.
Claim 2
Dependent Claim
136 words
Power transistor circuitry with current sensing comprising: a first output transistor connected to control conduction between an input terminal and an output terminal; means for selective application and removal of base drive current to said output transistor, said means comprising a current controlled feedback transformer, said current controlled feedback transformer having a secondary winding with a tap connected to a current source; means for monitoring the voltage of said secondary winding as an indication of the current conducted by said output transistor, said voltage exhibiting a change from a first low level to a second higher level upon the completion of the turn-off period of said output transistor; and means for initiating a turn-on base signal for a second output transistor in response to said change in voltage of said output voltage of said current source.
Claim 3
Dependent Claim
76 words
Power transistor circuitry in accordance with claim 1 wherein: said first and second output transistors are connected together as current controlled feedback transformer driven output transistors of a pole of a power inverter; and each of said output transistors have a current source connected with its transformer's secondary winding and the voltage of each said secondary winding is applied to control logic circuitry to initiate turn-on of one of said transistor when said voltage rises abruptly.
Claim 4
Dependent Claim
37 words
Power transistor circuitry in accordance with claim 2 wherein: said output transistors and said current controlled feedback transformers are physically disposed in a location remote from the location of said current sources and said control logic circuitry.
Claim 5
Dependent Claim
31 words
Power transistor circuitry in accordance with claim 1 wherein: said means for monitoring the voltage of said secondary winding comprises a lead connected directly to the output of said current source.
Claim 6
Dependent Claim
30 words
Power transistor circuitry in accordance with claim 1 wherein: said means for monitoring the voltage of said secondary winding comprises a lead connected to the end of said secondary winding.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-07-26 | 1986-01-25 | 1986-07-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-07-26 | 1990-01-25 | 1990-07-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-07-26 | 1994-01-25 | 1994-07-27 | $7700.00 | Window Closed / Lapsed |